KR101134638B1 - Method and appartus for digital rights management system in home network system - Google Patents

Abstract

A method and apparatus are provided in which a DRM proxy manages authentication regarding the use of media content to use DRM content from a media provider in a home network system.

The DRM proxy performs authentication with the media provider on behalf of the registered media player, and the registered media player uses the DRM content from the media provider without further authentication process after the DRM proxy performs authentication.

Digital Rights Management (DRM), DRM Proxy, Home Network, Bluetooth

Description

 Method and appartus for digital rights management system in home network system

1 is a conceptual diagram illustrating a configuration of a media provider, a DRM proxy, and a DRM media player according to an embodiment of the present invention.

2 is a conceptual diagram illustrating a process of using authentication and media content according to an embodiment of the present invention.

3 is a flowchart illustrating a process of using authentication and media content according to an embodiment of the present invention.

4 is a flowchart illustrating a process in which a DRM media player newly joins a home network according to an embodiment of the present invention.

5 is a flowchart illustrating a process of leaving a DRM media player from a home network according to an embodiment of the present invention.

6 is a flowchart illustrating a process in which a DRM proxy newly joins a home network according to an embodiment of the present invention.

7 is a flowchart illustrating a process of leaving a DRM proxy from a home network according to an embodiment of the present invention.

8 is a conceptual diagram illustrating a configuration in which a DRM media player shares media content with another DRM media player according to an exemplary embodiment of the present invention.

9 is a conceptual diagram illustrating a configuration in which a small media player plays DRM content received by a media player of a home network according to an embodiment of the present invention.

10 is a flowchart illustrating a process in which a small media player receives a DRM content received by a media player of a home network through a security process according to an embodiment of the present invention.

11 is a structural diagram showing a structure of a DRM proxy according to an embodiment of the present invention.

12 is a structural diagram showing a structure of a DRM media player according to an embodiment of the present invention.

13 is a structural diagram showing the structure of a small media player according to an embodiment of the present invention.

<Description of the symbols for the main parts in the drawings>

100: media provider 200: DRM proxy

300: DRM Media Player 400: Compact Media Player

Recently, researches on digital rights management (hereinafter referred to as "DRM") have been actively conducted, and commercial services using DRM have been introduced or are being introduced. The reason why DRM should be introduced can be derived from various characteristics of digital content. Unlike analog data, digital contents can be copied without loss, and easy to reuse, process, and distribute, but require much cost, effort, and time to produce. Therefore, if unauthorized copying and distribution of digital content is tolerated, it will violate the interests of digital content creators, and the creative intention of digital content producers will be diminished, which is a great obstacle to the activation of the digital content industry.

Efforts have been made to protect digital content in the past, but in the past, access to digital content was granted only to some people who paid for it, with a focus on preventing unauthorized access to digital content. However, if the payer deliberately distributes the digital content to a third party, the third party can use the digital content without paying for it. To solve this problem, the concept of DRM was introduced. DRM allows anyone unlimited access to any encrypted digital content, but to decrypt and execute encrypted digital content, you must have a license called the Rights Object. Therefore, applying the DRM can effectively protect digital content unlike the existing.

A system that makes much use of such digital contents is a home network system. A home network system refers to a technology in which two or more devices in a home communicate with each other, and devices in the home exchange information and control other devices through wired and wireless devices. In the past, home networks were limited to security-related parts, but recently, home networks have been expanding to multimedia viewing and broadcasting fields due to the rapid success of multimedia and the Internet. Thus, home networks now make it possible to identify faces through television screens watched in the living room and to open the door using a television remote control when an outsider visits. You can also watch movies played on a DVD player in your living room on your television in your bedroom, and you can watch your PC screen on your television. Finally, you can see and control the status of home appliances in your home through a secure network outside your home.

Meanwhile, with the improvement of networking technology and the development of internet technology, the Internet, wireless internet (mobile), and broadcast devices are gradually shifting to present a digital home environment in which a network is interoperable. In addition, the digital home environment is expected to be composed mainly of home servers, which are intelligent platforms such as next-generation set-top boxes, personal video recorders (PVRs), and PCs.

Based on this environment, typical home network DRM systems, such as Microsoft's media center and IBM's xCP, are structural features integrating traditional data networks that connect multiple PCs through gateway devices, entertainment, telephony, and home control networks. In accordance with the above, the service should be organized around the home media server, and the contents storage, management, and distribution functions will be in charge of delivering the multimedia contents and the corresponding license to the user device through the connection of the external internet and the home server. In this case, a group management function for the participating devices in the home network is provided together.                         

In addition, the transmission of multimedia content between home network devices has traditionally applied IEEE 1394 serial bus and universal serial bus (USB) based on Digital Transmission Content Protection (DTCP).

Home network devices for multimedia content services function as home media servers such as next-generation set-top boxes, PVRs, and PCs, and home media players such as TVs, web pads, and wireless monitors.

The home media server device should be able to provide DRM contents acquisition, recording, storage and sourcing to provide multimedia contents of the user's desire for DRM service by establishing an interoperation environment with various external networks. In addition, to support the DRM service, it provides security such as identification and access control for users and user devices, distribution of multimedia contents, and management of usage information such as clearing house.

In this regard, the home media player is a TV monitor, a stereo and home theater, a PDA, a multimedia mobile phone, a wireless monitor, a game console, and the like, and performs a function of playing and presenting DRM content within the allowances specified in the usage rights. Therefore, in the past, DRM rights management is performed in a home media server. 1) The home media server receives encrypted DRM content according to a user's request, and 2) the home media server decrypts the DRM content and then encrypts the internal network. Re-encrypted with a key, 3) the home media player that the user wants to play and present content receives from the home media server through the registration process, and 4) the home media player receives from the home media server. Re-encrypted DRM content is decrypted with an encryption key for the internal network, and then played and displayed.

This home media server is configured to provide a typical client-server type service, but this causes a problem in that DRM authentication and management are concentrated on the home media server. That is, since all DRM authentication and transmission of multimedia data are performed in the home media server, this causes a bottleneck. Moreover, since one or more media providers and one or more media playback devices are connected around one media server, there is a risk that the entire home network may be disconnected if a media server fails. Therefore, there is a need for a method of reducing the bottleneck and increasing the reliability of the home network and performing a fast process in DRM management. In the future, the structure of the network will be composed of peer-to-peer rather than the existing server, which will handle all the DRM tasks in one home media server. In particular, in the form concentrated in the home media server, the configuration of the home network may not be made dynamically, and the load on the home media server may be increased. As a result, multiple devices on the home network may not support dynamically accessing the home network, and may not be able to handle their dynamic changes.

An object of the present invention is to perform DRM authentication on behalf of DRM media players registered through one or more DRM proxies, and DRM media players in the home network that have undergone the authentication process receive content and rights objects directly from the media provider. To make it possible.

Another technical problem to be achieved by the present invention is to allow one or more DRM proxies to be distributed and processed so as to prevent the home network server from being stopped due to a server failure when the home media server manages the home network system.

Another technical problem to be achieved by the present invention is to enable DRM content to be shared in various ways in a home network, and to manage DRM based on a domain in which devices constituting these home networks can dynamically register and withdraw. To make it happen.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a method for managing a DRM system under a home network according to an embodiment of the present invention comprises the steps of: registering identification information of at least one media player, transmitting the registered information to a media provider; Requesting a media provider for a DRM certificate for a registered media player, receiving the requested DRM certificate from a media provider, and transmitting the received DRM certificate to the registered media player.

According to another embodiment of the present invention, a method for managing a DRM system under a home network may include generating a new group key when a new device requests registration, informing the media provider that the device is involved, and modifying it from the media provider. And receiving the received DRM certificate and encrypting the received DRM certificate to all registered devices.

According to another embodiment of the present invention, a method of managing a DRM system under a home network may include registering a corresponding device on a revocation list and generating a new group key when a registered device notifies the withdrawal, and the device withdrawn from the group key. And transmitting the revocation list to the media provider and the other devices.

According to an embodiment of the present invention, a method of using DRM content in a distributed home network may include requesting a registration of a media player with a DRM proxy, receiving a DRM certificate transmitted by the received DRM proxy, and receiving the DRM certificate. Receiving the DRM content from the media provider through.

According to an embodiment of the present invention, a method for providing DRM content under a home network may include receiving a request for DRM authentication from a DRM proxy, generating and transmitting the requested DRM certificate to a DRM proxy, and providing the device with the DRM certificate. Transmitting the DRM content.

A DRM proxy for managing a DRM system under a home network according to an embodiment of the present invention may include a storage unit that stores information about a registered media player, transmits information about the media player to a media provider, and sends a DRM certificate to the media provider. Sends a message requesting a message, transmits the DRM certificate to a registered media player, receives a DRM certificate from a media provider, and controls operations of the storage, the transmitter, and the receiver, and controls data between the components. It includes a control unit for exchanging.

In the home network according to an embodiment of the present invention, the DRM media player using the DRM content receives a DRM certificate transmitted by the DRM proxy, receives a DRM content provided by the media provider, a storage unit for storing the DRM certificate, Transmitter for transmitting a message requesting registration to the DRM proxy, Execution unit for playing the DRM content received from the receiving unit and controls the operation of the receiving unit, the storage unit, the transmission unit, the execution unit and exchanging data between each component It includes a control unit.

A small media player using DRM content under a home network according to an embodiment of the present invention may include a transmission unit that transmits a device ID and a key to a device that plays DRM content, and receives a DRM content that is transmitted by a device that plays DRM content. It includes a receiving unit, a control unit for decoding the DRM content received by the receiving unit, the control unit for data exchange between the transmitting unit and the receiving unit, and the execution unit for playing and executing the DRM content decrypted by the control unit.

According to one embodiment of the present invention, a DRM proxy for DRM management of a home network system and a DRM player for receiving and playing DRM certificates from the DRM proxy are executed. Meanwhile, the agency that issues the DRM content and the Rights Object for it is called a media provider. The relationship between these elements is detailed below.                     

The DRM content referred to in the specification is multimedia content to which DRM has been applied, and refers to content that is encrypted so that the user cannot execute or play the content unless an authorized user has permission. In addition, in order to execute and play the DRM content, the user must receive a right to play, play, etc., and having a right object for this is called a Rights Object. Rights Objects have rights to digital assets, and rights to play, display, execute, print, export, or view digital assets. This is the part to set.

A configuration according to an embodiment of the present invention includes a DRM proxy, a DRM player, and a media provider (MP), which is a media provider for issuing DRM content and rights objects to a user. DRM authentication under existing home network systems is done through a specific home media server. Therefore, if there are multiple media devices, the concentration on the home media server becomes severe and causes bottlenecks. In addition, this configuration eliminates the DRM management of one media server, and provides a way for each media device to freely use the multimedia contents.

Looking at the overall configuration according to an embodiment of the present invention as shown in FIG. In FIG. 1, media providers 100 providing media and DRM related rights objects and contents are connected to a wide area LAN (WAN), and various media players (DRM media players, 300) and DRM proxies (WRMs) forming a home network are illustrated. 200) is present. The DRM proxy 200 serves to make DRM authentication for other media players in the home network, and may have a function of a media player. In FIG. 1, the media player and the DRM proxies constituting these home networks form one domain. All media players in that domain will get the same authentication through the DRM proxy. After the authentication process, media players can use the media provider's DRM content. In addition, the DRM content may be simply encrypted and transmitted, and a right object defined for the right to use the DRM content may be transmitted together.

Prior to the description, the meaning of terms used in the present specification will be briefly described. However, it should be noted that the description of the terms is used to help the understanding of the present specification and does not limit the technical spirit of the present invention unless explicitly stated as limiting the present invention.

Wired and wireless technologies are used to connect devices in the home network. In the case of wired, Ethernet, HomePNA, power line control (PLC), IEEE 1394, USB (Universal Serial Bus), DVI (Digital Visual Interface) and HDMI (High Definition Multimedia Interface). Each of them is as follows.

1) Ethernet

Networking technology based on the IEEE 802.3 standard, a LAN technology that has long been proven in data communications. It is the foundation of home networks, including corporate networks, and is attracting attention for its speed (currently 10Mbps and 100Mbps), safety, high reliability and, above all, lower cost than competing technologies. Terminal devices connect to CAT-3 or CAT-5 unshielded twisted pair (UTP) wire or coaxial cable and use the CSMA / CD (Carrier Sense Multiple Access with Collision Detection) protocol. Currently, IEEE 802.3a, which has a transmission rate of 1,000 Mbps, is standardized and equipment using this technology is being released. Recently, new PCs are equipped with Ethernet LANs on Ethernet cards or motherboards, and consumer electronics vendors are also using Ethernet embedded set-top boxes, personal video recorders (PVRs), DVD players, video game consoles, and digital audio receivers. Marketed.

2) HomePNA

HomePNA, which is emerging as the backbone technology of the home network, can connect information and communication devices to one network using existing home telephone lines and establish a LAN environment without additional equipment such as a hub or router. HomePNA 2.0 at 10 Mbps is becoming the standard. Recently, HomePNA 3.0 of 128Mbps was introduced, which improves the transmission rate and enhances the quality of service (QoS). In mid-2004, leading products using HomePNA 3.0 will be introduced to the market. Although it is a relatively stable position among wired home networking technologies based on the advantages of using existing home telephone lines, it is a solid solution in terms of price, ease of use, security, and QoS, which are almost comparable to the wireless technology, which has recently emerged as a competitive technology. In need.

3) Power Line Communication (PLC)

PLC converts communication signal into high frequency signal of 100KHz ~ 30MHz by using power line installed in home or office and receives signal using high frequency filter when receiving.It has been used for data transmission for almost 20 years. do. The low speed (60bps) X-10 platform started off as an initial product, but because of the slow speed, it was unidirectional and the application was limited. Recently, since HomePlug 1.0 was introduced in late 2001, version 2 was redesigned and released at CES in early 2003, and the next generation of HomePlug AV is under development. The standard focuses on data and multistream entertainment, including HDTV and SDTV, and the product line is expected to be available in late 2004 or early 2005. Home networking technology using power lines is still relatively more expensive than Etehrnet or wireless technology. In the long term, it will likely be in the hands of consumer electronics or data transmissions that are not affected by QoS issues.

4) IEEE 1394

IEEE 1394, also known as FireWire, is a next-generation core technology that enables high-speed, real-time data transmission as a serial bus-based digital interface technology that is gained thanks to the digitization of AV devices and the provision of a multimedia environment. Up to 63 terminals can be connected, and IEEE 1394a can communicate at speeds of up to 400Mbps at 4.5m and IEEE 1394b at 800 ~ 1600Mbps at 100m. The main advantage of IEEE 1394 as a network transport standard is that both the consumer electronics industry and the PC industry accept it as the next generation of data transport standards. Digital cameras, digital VCRs, and high-capacity data storage devices already incorporate an IEEE 1394 interface, which will soon be introduced in consumer PCs. This technology is expected to be a practical application as a backbone technology in an entertainment network or in a home or multi-family house in the same room.

5) Universal Serial Bus (USB)

USB has the advantages of being a Human Interface Device (HID), easy connection to peripherals, sufficient interrupt request (IRQ) resources, and support for Plug and Play (PNP) features, while relatively low power sources The high CPU share is pointed out as a disadvantage. It can be divided into USB V1.0 with 12Mbps and USB V2.0 with 480Mbps. Most USB products on the market are manufactured to 1.1 specification.

6) Digital Visual Interface (DVI) and High Definition Multimedia Interface (HDMI)

DVI and next-generation HDMI are HDCs (video over DVI and video and audio over HDMI) as digital interconnects, enabling secure, uncompressed transmission. These technologies deliver stable transmission efficiency and can deliver high-precision content (including eight channels via HDMI). Many recent HDTV models, including PC monitors, have DVI. Along with IEEE1394, it is competing as a solution for A / V device networking.

Recently, as the research on wireless technology has been actively conducted, attempts have been made to overcome the limitations of mobility of wired communication, and many researches have been conducted on wireless home networks. The wireless communication is as follows.                     

1) IEEE802.11x

It is emerging as a wireless home networking technology because it does not require cable wiring and is a form of communication that can be connected to the base LAN even when mobile, and the LAN configuration is quick and the network structure can be easily changed. There are various wireless technology standards such as 802.11b, 802.11a, 802.11g, 802.11e and 802.11i. Among them, 802.11b is a standard competition between HomeRF and wireless home networking technology, but recently, due to the high speed and high volume of products, Has an edge in. 11Mbps products, which developed the existing 2Mbps standard, are being sold in the market and are leading in the practical screen. Compatibility certifications also ensure that a network of products from multiple companies is blended together.

2) Home Radio Frequency (HomeRF)

Standardized by companies leading the PC, peripherals, communications, software, and semiconductor industries, the standard for the SWAP (Shared Wireless Access Protocol) 1.1 standard has been completed. Although it aims to build a network in the home using RF method, not infrared, it has the disadvantage that the speed decreases depending on the somewhat slow speed of 1 ~ 2Mbps and the number of connected devices. to be. Like 802.11b or Bluetooth, it uses the 2.4 GHz band and can connect up to 127 devices.

3) Bluetooth

It is a low-power, low-cost, short-range wireless communication technology that enables communication between various devices within a distance of about 10m.In the early days, it was limited in the scope of application, but recently, its functions have been expanded so that personal communication devices such as mobile phones and PDAs, headsets / keyboards, etc. PC peripherals such as / speakers / printers, and a personal area network (PAN) construction technology between devices connected to a wired PC has been in the spotlight. As one of the representatives of the next generation network technology, it is currently showing a maximum transfer speed of 1Mbps among devices within 10m, but a 10Mbps version is under development, and it is expected to replace the USB function in a wired or new application in a mobile product. However, relatively expensive module prices are hampering widespread commercialization, and growth is expected in the handsets and headsets.

4) Ultra-wideband (UWB)

It was primarily used for special purposes such as military radar or remote detection, and was licensed as a commercial technology by the FCC in February 2002. In the early stages of application in the field of communication, evaluation samples of UWB chipsets for wireless video transmission such as VTRs and DVD players have been released. Since 2003, development of 100Mbps chips for wireless video transmission in homes is expected. It is difficult to expect a leading role in home networking in the near future, but in the long run, it is expected to play some role in networking AV equipment, depending on the standardization and application efforts of major vendors.

On the other hand, there are public key cryptography and symmetric key cryptography.

Public-key Cryptography

Also known as asymmetric encryption, this means that the key used to decrypt the data is different from the key that encrypts the data. The public key encryption algorithm is open to the public, and public key encryption has a characteristic that a third party cannot know or find the original text only with the encryption algorithm, the encryption key, and the encrypted sentence. Examples of public key cryptographic systems include Diffie-Hellman cryptographic systems, RSA cryptographic systems, ElGamal cryptographic systems, and elliptic curve cryptographic systems. In the case of public key encryption, it is about 100 ~ 1000 times slower than symmetric key encryption, so it is used for key exchange or digital signature rather than for encrypting the content itself.

Symmetric-key Criptography

Also known as secret key encryption, this means that the key used to encrypt the data and the key used to decrypt the data are the same. As an example of such symmetric key encryption, DES is most commonly used, and recently, an application using AES is increasing.

The process of receiving the DRM content and the rights object according to the configuration of FIG. 1 is shown in FIG. 2. Unlike the conventional home media server, the authentication and content receiving method according to an embodiment of the present invention is divided into two parts. First, the authentication part is described as follows. The DRM proxies 206 and 208 receive authentication for players belonging to their own domain, that is, the home network (S210). This DRM proxy may be internal to the home network or external to the home network. This is because the DRM proxy performs authentication on behalf of the devices in the domain that requested the registration. The DRM proxy assigns a common key (group key, hereinafter referred to as 'group key') to the players 300 registered to it, and manages this key. The DRM proxy is registered with the DRM proxy server for the media provider. Ask players to do DRM authentication. The media provider reviews these requests and gives the proxy server a DRM certificate that allows players registered with these proxy servers to use their media, which is then encrypted with a group key and registered with the media. Pass this certificate to the player.

Next, a description will be given of the part receiving the content. With the received certificate, the players in the domain inform the media provider that they are legitimate users (s220), and the media provider reviews the certificate and sends the DRM content to the media player (s230). In this process, a right object for encrypted DRM content may also be sent. Therefore, the bottleneck that the home media server plays the role of DRM authentication and content delivery can be reduced.

FIG. 3 sequentially shows an embodiment of the present invention for accessing DRM authentication and contents shown in FIG. 2.

The media provider 100 of FIG. 3 has a DRM content and a rights object. The DRM media player 300 that plays and expresses the DRM content must receive a right from the media provider to execute the DRM content. The DRM proxy 200 plays a role of relaying the DRM content. FIG. 3 assumes a case where several DRM players request registration in one DRM proxy, and a case in which one DRM player requests registration will be described later. The DRM player first requests the DRM proxy to register itself by transmitting the device ID and device key of the DRM player (s205). Then, the DRM proxy transmits a group key to the verified DRM player (s207). This group key means a common key of all DRM players participating in the home network. Players having the same group key receive DRM authentication-related management through the DRM proxy. In addition, the group key is a key that all DRM players currently participate in common, and when one or more players register or withdraw, a new group key can be generated. Thus, at any given time, all players in the domain have a common group key.

After transmitting the group key, the DRM proxy transmits a message including information about players registered to the media provider to the media provider (S210). After receiving the message, the media provider checks the group information of the players registered in the DRM proxy in the received message (s211), and then transmits a message indicating that the confirmation has been made to the DRM proxy (s213). Thereafter, the DRM proxy requests the media provider through the message “Security Association” for the DRM certificate required for the DRM players registered by the DRM proxy to execute the DRM content (S215). In order to secure the DRM certificate, the DRM proxy preferably encrypts the message and transmits the message. Then, the media provider analyzes the transmitted encrypted message, and if there is no error, transmits the DRM certificate to the DRM proxy through a message called Security Response (s217). In this case, it is preferable to encrypt and transmit the DRM certificate. . That is, the DRM proxy decrypts the received DRM certificate again and transmits it to the DRM players in the home network registered with it (s219). In this case, the DRM proxy encrypts the certificate with the aforementioned group key and transmits it. Accordingly, the players in the home network, that is, the domains have a common certificate, and with this certificate, the DRM players inform the media provider that they are an authenticated user (s220), and the rights object (rights information, which is the right information about the content) Right Object) and media content are received (S230). The Security Association and Security Response mean that a message is encrypted and transmitted between a media provider and a DRM proxy. This encryption can be performed through various encryption techniques such as the above-described public key method or symmetric key method.

In the above-described embodiment, the various DRM players constituting the home network do not request the DRM certificate directly from the media provider at one time, but after the DRM proxy verifies the DRM players under their home network, By requesting the DRM certificate from the media provider, it is possible to reduce the DRM certificate request that is concentrated on the media provider. On the other hand, the DRM proxy plays a role of managing the certificate, which is not the nature of the DRM certification authority that directly issues the certificates for the players. The role of the DRM proxy can prevent the centralization of authentication requests to the media provider or home media server.

3 illustrates a process in which one or more DRM media players request registration in a situation where another DRM media player has not registered. However, DRM players do not always connect to the home network at the same time, but may connect at any unspecified time. One or more players may be newly registered in the existing configured home network, and one or more players may leave. In this case, the DRM certificate issued by the DRM proxy is issued to the group that constitutes the entire home network. Therefore, if such registration or withdrawal occurs, the group has changed. Therefore, the group needs to be reconfigured and the group key generated again. have. Hereinafter, a description will be given with reference to FIGS. 4 and 5.

First, a case in which the DRM player newly requests registration in FIG. 4 will be described. When the user requests to register the new player 301 as a DRM player (S410), the DRM proxy 200 generates a new group key including the corresponding device (S420), and the new device participates in the media provider 100. Notify (S430). Then, the media provider generates a newly modified DRM certificate based on this and delivers it to the DRM proxy (S440). The received DRM proxy encrypts and transmits the modified DRM certificate and the new group key to the newly registered player 301 with the device key of the player (S450), and the previous group key for the existing players 305. The newly fished DRM certificate and the new group key are transmitted (S460). The newly registered player 301 does not know the previous group key and encrypts it with the device key of the player. However, the existing player 305 knows the previous group key and transmits the encrypted group with the previous group key.                     

As a result, the existing group key is changed to the new key before the new player joins. By modifying the group key, all media players in the domain have a new common group key. In the embodiment illustrated in FIG. 4, the media provider generates a modified DRM certificate. Alternatively, the media provider may encrypt and send a group key to a new player while maintaining the existing certificate. In another embodiment, the group key used in the related art can be used as it is without generating a new group key.

5 shows a process of withdrawing the DRM player existing in the home network. An opted out DRM player needs to take steps to ensure that they can no longer request content from the media provider. There is no need to issue a new certificate for the withdrawn DRM player, it is only necessary to reject the service request for the DRM player. Therefore, it can be deployed as shown in FIG. First, the DRM player 302 who wants to withdraw informs the DRM proxy 200 that he or she is withdrawn (s510). The received DRM proxy registers the player in the revocation list associated with the DRM certificate and generates a new group key (s520), and other DRM players other than the DRM player 302 notifying the group key to leave. Encrypted and transmitted to (305) (s530). As a result, the withdrawn player cannot work through the new group key because he knows only the existing group key. The DRM proxy may periodically transmit the revocation list to the media provider 100 and all the DRM players 305 in the home network (s540 and s550) to have information about the withdrawn DRM player. Even if the player who has withdrawn from the media provider knows the new group key and requests the data, the media provider will reject the request with reference to the revocation list. In addition, by transmitting a revocation list to other players, it is possible to query whether a player withdraws when a given player requests content shared between players. Access to the contents of the withdrawn player is prevented through the aforementioned group key update and revocation list inquiry. The case of sharing the content will be described later with reference to FIG. 8.

There can be multiple DRM proxies in a home network. Multiple DRM proxies can reduce the bottleneck that an excessive number of DRM players in a home network request DRM authentication to one DRM proxy. In this case, information exchange between multiple DRM proxies is necessary because registration and withdrawal of a specific DRM player occurs for one DRM proxy, so other DRM proxies need to know this information as well. First, a case in which a new DRM proxy is registered will be described with reference to FIG. 6. The whole flow is the same as the registration of the DRM player of FIG. When a new DRM proxy 201 requests registration with an already existing DRM proxy 200 (s610), the existing DRM proxy generates a new group key (s620), and a new DRM proxy is transmitted to the media provider 100. Inform the participation (s630). When the media provider generates the modified DRM certificate based on this and transmits the modified DRM certificate to the DRM proxy 200 (s640), the DRM proxy encrypts the modified DRM certificate and the new group key with the device key of the new DRM proxy 201 to generate a new DRM certificate. It transmits to the DRM proxy 201 (s650), and also encrypts the modified DRM certificate and group key with the previous group key and transmits it to another DRM proxy (s205) (s660). Since the newly registered DRM proxy 201 does not know the previous group key, it is encrypted with the device key of the newly registered DRM proxy 201. However, since the existing DRM proxies 205 know the previous group key, they can be transmitted by encrypting with the previous group key. Do. Each of the DRM proxies encrypts the modified DRM certificate and the new group key with the old group key to the DRM players registered with it (s670). The media provider generates a modified DRM certificate, but in another embodiment, a method of encrypting and sending a group key to a new DRM proxy while maintaining the existing certificate may be possible. In another embodiment, the group key used in the related art can be used as it is without generating a new group key.

FIG. 7 illustrates a case in which a DRM proxy leaves a home network in which two or more DRM proxies participate. This is similar to the withdrawal of the DRM player in FIG. The DRM proxy 202 intends to withdraw notifies another DRM proxy 200 of its withdrawal (s710). The notified DRM proxy registers the withdrawn DRM proxy in the revocation list associated with the DRM certificate, generates a new group key (s720), and encrypts it to another DRM proxy except for the above-mentioned withdrawn DRM proxy. s730). The DRM proxy transmits the received new group key to the DRM multimedia player 300 registered therein (S740). The revocation list is periodically transmitted to the DRM proxy and the media provider so that the other DRM proxy and the media provider also maintain the revocation list (s740 and s750). Similarly, each DRM proxy transmits a revocation list to the DRM players registered with it (s760). The revocation list allows media providers and media players to learn about the DRM proxy that has been withdrawn, and prevents the withdrawn DRM proxy from participating in sharing content between players in the domain.

In FIG. 8, DRM players in a domain share one content. Parts related to the authentication of FIG. 8 are the same as those described with reference to FIGS. 2 and 3. Here, in step s230, the TV 306, which is a media player that receives a right object, video, audio content, or stream, shares its received content with another DRM proxy 208 or an audio set 308, which is another media player. can do. As described with reference to FIGS. 5 and 7, when a player or a DRM proxy is withdrawn, a revocation list may be generated and transmitted to another DRM proxy or the player (s241, s243), thereby attempting to share content by a device that has already been withdrawn. Can be prevented double.

In addition, in FIG. 8, the DRM proxy that receives authentication authority from the media provider is not the DRM proxy 208 existing in the domain, but the DRM proxy 206 existing outside the domain. The DRM proxy does not have to be present in the domain to be authenticated. Since the DRM proxy handles authentication of devices in its own domain, it is also possible to authenticate outside the domain and then send the authorization to the domain. Therefore, it can be seen that the existing home media server is different from the domain-specific authentication.

When DRM management is performed according to an embodiment of the present invention, DRM authority information and content access are dualized to improve speed, and a home media server is not required. On the other hand, DRM players exist that can perform complex DRM-related encryption, such as TVs and audio sets, but some devices that can only decrypt and transmit and receive data, such as simple headsets. In particular, in recent years, technologies for wired and wireless home networks have been developed. In particular, as wireless RF communication under HomeRF, Bluetooth, UWB, and IEEE 802.11 related to wireless home networks has become available, development of compact media players such as Bluetooth headsets has been made. . However, incorporating DRM-related technology into such a small media player may result in excessive development cost of the small media player. For that reason, however, attempts to protect digital multimedia content through DRM are difficult unless there are any restrictions on the transfer of information between these small media players and media players. Therefore, a method different from that between the above-described DRM player and DRM proxy is required. This is illustrated in FIGS. 9 and 10.

First, a schematic structure of FIG. 9 is as follows. In FIG. 9, a Bluetooth headset which is one of the small media players is taken as an example, but the present invention is not limited to the Bluetooth headset, and the above-described technology used in the wired and wireless home networks may be used. In FIG. 9, the Bluetooth headset 400 does not directly request content from the media provider 100. The multimedia content is received by the DRM proxy 200 or the DRM player (not shown in the figure, but the DRM media player can act as a DRM proxy) from the media provider through the authentication process described above. This received data is requested by the Bluetooth headset to the media player or the DRM proxy 200. In this process, the multimedia content is decrypted by the DRM proxy (or DRM media player) and encrypted again. To form a safe channel. Content transmitted through this encryption is decrypted again in the Bluetooth headset and finally sent to the user.

Operation according to an embodiment of the small media player shown in FIG. 9 is the same as FIG. Since the DRM proxy 200 also has a function of a media player, that is, a function of playing and executing media, the DRM proxy 200 may operate with a small media player. This can be easily seen by looking at PCs and mobile phones. When the DRM proxy / player 200 notifies the small media player 400 to transmit the DRM content (s910), the small media player requests an authentication challenge message through the Authentication Challenge message (s920). At this time, the user ID for authentication, the device key of the small media player, and a random number are sent as a hash. At the DRM proxy / player side, the device key, group key, and random number of the DRM proxy / player ID and the small media player are configured with a hash to perform authentication using an authentication response message (s930). When the authentication is made, the DRM content is delivered using the group key (s940), and the small media player decrypts and plays the content (s950).

The structure of a small media player such as a DRM proxy, a DRM media player, and a Bluetooth headset that receives and executes media content from them are as follows.                     

The term 'component', '~' or 'module' used in this embodiment means software or a hardware component such as an FPGA or an ASIC, and a module plays a role. However, modules are not meant to be limited to software or hardware. A module may be configured to reside on an addressable storage medium and configured to play back one or more processors. Thus, as an example, a module may include components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, procedures, subroutines. , Segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and modules may be combined into a smaller number of components and modules or further separated into additional components and modules. In addition, the components and modules may be implemented to play one or more CPUs in a device or secure multimedia card.

11 shows the configuration of the DRM proxy 200. The DRM proxy 200 is largely comprised of a controller 210, a storage 220, a transmitter 230, a receiver 240, an encryption unit 250, and a content execution unit 260. The storage unit 220 stores information on the DRM media player requesting registration thereof, and also stores a group key generated in this process and a DRM certificate to be transmitted to the DRM media players. It also has a revocation list that records the information of the leaving media players, which are periodically sent to media providers, media players, and other DRM proxies. In addition, the storage unit 220 may directly store the media content or the rights object for the content. The stored content can be transferred to another media player.

The transmission unit 230 sends a group key and a DRM certificate to the media player, and also sends a message requesting the media provider to issue information and registered DRM certificates of the registered devices. In this process, encryption is required for the security of the transmitted message. The encryption unit 250 performs this operation. On the other hand, when a small media player other than the media player wants to execute the content, it is difficult for the small media player to have an operation unit capable of performing DRM-related operations. 230). In this process, the encryption unit 250 provides a function by encrypting the content transmitted to the small media player.

The receiver 240 receives a registration or withdrawal request from a media player or another DRM proxy 200, receives a message from a media provider, or receives a DRM certificate. In addition, since the DRM proxy 200 directly executes the content, the receiving unit 240 also has a function of receiving the media content to be delivered to the content executing unit 260.

As described above, the encryption unit 250 performs encryption and decryption for security in exchanging information and transmitting content with a media player, a media provider, or a small media player. In particular, since the DRM certificate sent by the media provider is encrypted and transmitted, in order to deliver it to the media player, a function of decrypting and re-encrypting the group key of the media player is required.                     

The content execution unit 260 is included when the DRM proxy 200 also has a function of a media player, and plays a role of playing and executing content. It is capable of acting as a DRM proxy 200 with excellent arithmetic processing capabilities such as mobile phones, computers, PDAs, and laptops, but also has the ability to receive video, audio information, or streams within itself. Because you can play. The content executor 260 supports such a play and play function.

The controller 210 plays a role of instructing each component constituting the DRM proxy 200 to pass data to other components or to process them in the middle after performing their functions.

12 shows the structure of the DRM media player 300. Similar to the DRM proxy, the controller 310, the storage 320, the transmitter 330, the receiver 340, the encryption unit 350, and the content execution unit 360 are configured. However, the functions of each part of the DRM proxy 200 are different.

The storage unit 320 stores the group key generated during registration with the DRM proxy, and stores the DRM certificate received by the DRM proxy from the media provider. In addition, the DRM certificate has a function of not only playing and executing DRM contents received from a media provider but also storing the contents. The storage unit 320 stores the contents.

The transmitter 330 transmits a message informing the DRM proxy of its registration and withdrawal, and then receives a DRM certificate and transmits a message for requesting media content to the media provider. Since the information transmitted by the DRM media player 300 is not information that requires much security, encrypting a message before transmission depends on the situation of the system. On the other hand, when a small media player such as a Bluetooth headset attempts to receive media content, the DRM media player 300 needs to transmit the media content it receives to the small media player. Send the content.

On the other hand, the receiving unit 340 receives the group key and the DRM certificate from the DRM proxy, and the DRM certificate is encrypted and transmitted because it is information requiring security. Therefore, the receiver 340 needs to interact with the encryption unit 350 that decrypts the received information. In addition, the receiver 340 receives the media content from the media provider.

The encryption unit 350 decrypts the data received from the DRM proxy and the media provider, and encrypts the content when the media content is transmitted to a small media player such as a headset.

The content executor 360 is responsible for playing and playing the media, which can be easily understood by taking a TV, an audio set, and the like as an example. The content executor 360 decodes and plays the content transmitted by the media player 300 through the receiver 340, and the played and executed content may be shared with other media players.

The function of controlling the interaction between the respective components of the media player 300 is performed by the controller 310. Although it does not require much more computational processing than DRM proxy, it requires some computing power because it performs the DRM authentication process and exchanges data registered, withdrawn and transmitted and received.

As shown in FIG. 13, the small media player 400 such as a Bluetooth headset has a simpler configuration than the DRM proxy and the media player. It is largely composed of a control unit 410, the transmission unit 430, the receiving unit 440, the execution unit 460. The transmitter 430 transmits its information to the DRM playback device to which the small media player 400 is connected, that is, the DRM proxy having a DRM media player or DRM media player function. This is to maintain the security of the DRM content delivered between the DRM media player and the small media player 400. With this information, the DRM media player transmits the encrypted DRM content, which is received by the receiver 440 to execute the content through a decryption function of the controller 410. Since the small media player 400 is intended to use media contents under a home network with a simple configuration, the small media player 400 does not have a special function for storing or sharing complicated media contents and registering with the DRM proxy.

Those skilled in the art will appreciate that the present invention can be embodied in other specific forms without changing the technical spirit or essential features of the present invention. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the scope of the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalent concept are included in the scope of the present invention. Should be interpreted.

By implementing the present invention it is possible to eliminate the bottleneck caused in using the DRM content through the home media server, which has been a problem. In particular, in configuring a home network, a DRM proxy and a DRM media player can be dynamically registered and withdrawn, and DRM content can be shared among devices in a domain that constitutes the same home network.

In addition, the present invention can improve the reliability of the home network system, even if a problem occurs in any one of the DRM proxy, the other DRM proxy can manage the DRM player in the domain.

In addition, the present invention enables a small media player to use DRM content to protect copyright.

Claims (49)

Storing information of the media player; Transmitting the stored information to a media provider; Requesting a media provider a DRM certificate for the media player; Receiving the requested DRM certificate from a media provider; And Sending the received DRM certificate to the media player, The media player manages a DRM system under a home network that receives DRM content from the media provider using the DRM certificate. The method of claim 1, The storing of the information includes receiving a message requesting registration from the media player. Wherein the information includes a device ID and a device key of the media player. The method of claim 1, Transmitting the group key to the media player after storing the media player information; And Encrypting the received DRM certificate with the group key and transmitting the encrypted DRM certificate to the media player; The method of claim 3, Encrypting the DRM certificate with the group key includes decrypting the received DRM certificate encrypted by the media provider and encrypting the received DRM certificate with the group key. The method of claim 1, Authenticating with the small media player when the small media player is connected after transmitting the DRM certificate to the media player; And And delivering the encrypted DRM content to the small media player based on the authentication. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete A storage unit for storing information about the media player; And Sending a message for requesting information and the DRM certificate for the media player to the media provider, and a transmission unit for transmitting the received DRM certificate to the media player in response to the transmission of the message, The media player is a DRM proxy for receiving DRM content from the media provider using the DRM certificate. 28. The method of claim 27, And a receiving unit receiving the acknowledgment message that the information is transmitted after the transmitting unit transmits the information to the media provider. 28. The method of claim 27, The information is a DRM proxy composed of the device ID and device key of the media player. 28. The method of claim 27, It further includes a control unit for generating a group key to store in the storage unit, The transmitter transmits the generated group key to the media player. 31. The method of claim 30, The DRM proxy further includes an encryption unit for decrypting the DRM certificate received from the media provider and encrypting it with the group key. 31. The method of claim 30, The controller may modify the group key when a new device requests registration. 31. The method of claim 30, The controller may modify the group key when the registered device notifies the withdrawal. 28. The method of claim 27, The storage unit stores a DRM proxy for revocation list of the withdrawn devices 28. The method of claim 27, DRM proxy further comprises an execution unit for playing and executing the DRM content 28. The method of claim 27, The transmitter transmits the DRM content to the connected small media player. The method of claim 36, The DRM proxy further comprises a password unit for performing authentication with the small media player. delete delete delete delete delete delete delete delete delete delete delete delete

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